A new old bug in the printer ROM?

[Tinue]

(10-23-2023 01:04 PM)MeindertKuipers Wrote:  The IR communication protocol between the calculator and the HP82240 printer is actually quite well defined.

Maybe I misunderstood brouhaha, but I think he was talking about the interface inside of the 82242 module. Similar to the way the printer emulators are set up, there will be a part that produces the bytes going to be sent over infrared, and a part that produces the IR pulses out of the bytes.

Nowadays, the IR pulse producer is a microcontroller (Arduino or similar), and possibly in the 82242 module it is set up similarly. If this interface were understood, then one could use the original ROM code of the module, capture the produced bytes and send them to the modern implementation of the pulse producer that is built in to the DM41X.